This application relates to welding apparatus and systems and, particularly, to arc welding systems such as Metal Inert Gas (xe2x80x9cMIGxe2x80x9d) arc welding systems.
Typically, a MIG welding system includes a welding gun or torch assembly which feeds a consumable wire electrode through a current pick-up tip which applies welding potential to the electrode. The gun or torch assembly includes a main housing to which is removably mounted a welding nozzle which surrounds the welding tip and may channel an inert shielding gas to the welding arc. The nozzle assembly may be air or water cooled. The welding gun or torch assembly must be serviced with the utilities which it requires for operation, such as water for cooling, gas for shielding the welding arc and electricity to effect the welding, as well as being provided with the consumable wire electrode. All of these utilities are fed to the welding gun or torch assembly from associated supplies via utilities delivery means, which may include a portable utilities station of the type disclosed in my U.S. Pat. No. 4,210,796.
When the welding system is to be utilized in mechanized or automated applications, the welding torch assembly is in the form of a machine barrel which is fixedly mounted on the automated welding control equipment. For example, the machine barrel may be mounted on a permanent fixed mount to which workpieces are delivered for welding or, alternatively, might be mounted on a movable mount, such as that of a robotic welding machine, which moves to the workpiece under remote control, and which may be pre-programmed.
It is known to provide nozzles and welding tips in such welding systems which are easily replaceable without disconnection of the systems from utilities supplies, arrangements of this type being disclosed, for example, in my U.S. Pat. Nos. 4,600,824 and 4,582,979.
In certain types of MIG welding applications, it is desirable to utilize two separate electrodes, and it is known to provide such dual-electrode or twin welding devices. However, heretofore, such dual-electrode devices have not afforded easy removability and replaceability of parts without requiring disconnection of utility supplies, as was afforded in the single-electrode devices of my aforementioned patents.
Furthermore, it is sometimes desirable to operate the two electrodes of a dual-electrode welding apparatus from two different power supplies, referred to herein as a xe2x80x9ctandemxe2x80x9d arrangement, and prior systems have not adequately provided for this.
This application discloses an arc welding apparatus which avoids the disadvantages of prior apparatuses while avoiding additional structural and operating advantages.
An important aspect of the invention is the provision of a dual-electrode arc welding apparatus which includes a current-pickup tip assembly which can be simply and easily removed and replaced without affecting any utilities supplies.
A further aspect is the provision of a welding apparatus of the type set forth, which permits removal of the tip assembly without affecting the position of the remainder of the apparatus. of the type set forth which utilizes different types of removable tip assemblies.
A still further aspect is the provision of an apparatus of the type set forth, wherein the tip assembly is coupled to the apparatus via an adapter which is also removably mountable independently of a surrounding nozzle assembly.
Yet another aspect is the provision of an apparatus of the type set forth, wherein the two electrodes are respectively provided with separate power supplies.
Certain ones of these and other aspects may be attained by providing, in an arc welding apparatus for delivering two wire electrodes to a workpiece and including a body assembly adapted to be coupled to a source of electric power and directing the electrodes toward a working end of the apparatus, and a nozzle assembly removably coupled to the body assembly for channeling other utilities to the working end, the improvement comprising: an adapter electrically and mechanically coupled to the body assembly for receiving the electrodes therefrom and maintaining the electrodes spaced from each other, and a tip assembly removably mounted on the adapter in electrical connection therewith and defining two channels for respectively slidably receiving and electrically contacting the electrodes and guiding them to the associated workpiece, whereby the tip assembly is removable from the apparatus without removing the nozzle assembly or the adapter.
Other aspects may be attained by providing a body assembly with first and second discrete bodies electrically insulated from each other and respectively connected to separate power supplies.